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Vishay General Semiconductor - Diodes Division SMAJ51AHM3/I
- Part No.:
- SMAJ51AHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51AHM3/I.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,473
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Product details
Overview
SMAJ51AHM3/I from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 51 V standoff voltage (VWM), 56.7–62.7 V breakdown range (VBR at 1 mA), 82.4 V maximum clamping voltage (VC) at 4.9 A peak pulse current, and 400 W peak pulse power rating (10/1000 μs waveform). It is widely deployed to protect MOSFETs, ICs, and sensor signal lines in automotive and industrial power supply rails.
For engineers reviewing the SMAJ51AHM3/I datasheet, SMAJ51AHM3/I pinout, SMAJ51AHM3/I application, or SMAJ51AHM3/I equivalent, this device serves as a halogen-free, RoHS-compliant, AEC-Q101-qualified TVS for high-reliability DC rail and interface line protection where fast response (<1 ns), low clamping ratio (1.62×VWM), and stable thermal performance up to +150 °C junction temperature are required.
Technical Context
This unidirectional TVS operates by avalanche breakdown when reverse voltage exceeds its VBR threshold, diverting surge energy away from protected circuitry. Its glass-passivated junction ensures stable leakage (<1 μA at 51 V) and repeatable clamping behavior across temperature (-55 °C to +150 °C).
The device delivers 400 W peak pulse power (derated to 300 W above 78 V) with low incremental surge resistance and excellent clamping capability-critical for suppressing ESD, lightning-induced transients, and inductive switching spikes on 48 V and 54 V systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 51 V - Maximum continuous reverse operating voltage before significant conduction begins; defines safe DC operating margin. |
| VBR (Breakdown Voltage) | 56.7–62.7 V at 1 mA - Tight tolerance ensures predictable turn-on during overvoltage events without premature triggering. |
| VC (Clamping Voltage) | 82.4 V at 4.9 A (10/1000 μs) - Limits downstream voltage stress to <1.62×VWM, protecting 60 V-rated components. |
| PPPM (Peak Pulse Power) | 400 W - Sustains standardized 10/1000 μs surges common in ISO 7637-2 and IEC 61000-4-5 testing. |
| IPPM (Peak Pulse Current) | 4.9 A - Peak surge current handled at rated clamping voltage; enables protection of medium-energy transients. |
| TJmax | +150 °C - Enables operation in under-hood automotive and high-ambient industrial environments. |
| Package | SMA (DO-214AC) - Surface-mount package with 5.0 mm × 5.0 mm copper pad thermal design, MSL Level 1 compatible. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; cathode indicated by band marking on unidirectional variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction path / surge return path | Connected to ground or low-impedance return plane; completes clamping loop during transient events. |
| Cathode | Protected line connection / high-side terminal | Connected to the line being protected (e.g., 51 V rail); reverse-biased during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control, body electronics, and ADAS power domains. |
| Halogen-free & RoHS-compliant (HM3 suffix) | Meets global environmental compliance requirements without compromising surge robustness or thermal reliability. |
| 400 W peak pulse power (10/1000 μs) | Handles high-energy transients per ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Level 3/4 test profiles. |
| Low clamping ratio (1.62×VWM) | Minimizes voltage overshoot during clamping, reducing risk of latch-up or gate oxide damage in downstream FETs/ICs. |
| Fast response time (<1 ns) | Activates before most semiconductor failure mechanisms initiate, enabling effective protection of high-speed interfaces. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
|
Use Scenario: Protecting 48 V/54 V battery-supplied ECUs against load dump and alternator transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp surges exceeding 51 V. Use Value: Maintains system uptime by preventing damage to microcontrollers and CAN transceivers during ISO 7637-2 Pulse 5a events. |
Use Scenario: Shielding analog output lines of pressure/temperature sensors from ESD and cable discharge events. IC Role / Device Role / Timing Role: TVS connected between signal line and ground, leveraging fast response to suppress sub-100 ns ESD pulses. Use Value: Preserves measurement accuracy and prevents sensor reset by limiting transient-induced voltage excursions to ≤82.4 V. |
| DC-DC Converter Input Protection | Motor Drive Gate Driver Protection |
|
Use Scenario: Safeguarding buck converter inputs against back-EMF and hot-swap surges in factory automation systems. IC Role / Device Role / Timing Role: Placed upstream of input capacitors to absorb repetitive 400 W transients without degradation. Use Value: Extends converter lifetime by eliminating cumulative stress on input MOSFETs and controller ICs. |
Use Scenario: Clamping Miller-induced voltage spikes on high-side gate drive lines in 3-phase inverters. IC Role / Device Role / Timing Role: Connected between gate and source of SiC/GaN FETs to limit dv/dt-induced false turn-on. Use Value: Prevents shoot-through failures by clamping gate-source transients to safe levels below driver IC absolute max ratings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51AHE3/I | Same electrical specs but RoHS-compliant (non-halogen-free) version; no halogen-free certification. | Acceptable for commercial/industrial use where halogen-free mandate does not apply. | Select SMAJ51AHE3/I if halogen-free requirement is waived and cost optimization is prioritized. |
| SMAJ51A-M3/5A | Identical electrical and thermal specs; differs only in packaging format (13" reel, 7500 pcs) and base P/N suffix. | No functional difference; suited for high-volume SMT production with larger reel logistics. | Choose SMAJ51A-M3/5A when matching existing tape-and-reel infrastructure or volume procurement targets. |
Compared with SMAJ51AHM3/I, SMAJ51AHE3/I lacks halogen-free compliance but offers identical surge performance, while SMAJ51A-M3/5A provides identical protection capability in a different reel configuration-neither is pin-compatible in the sense of mechanical interchangeability, but all share identical SMA footprint and electrical behavior.
Availability
SMAJ51AHM3/I is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and DC-DC converter input surge suppression requiring stable component supply, long-term lifecycle support, and AEC-Q101 assurance.
Supply support for SMAJ51AHM3/I includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, and protection devices with emphasis on reliability, efficiency, and application-specific validation.
The SMAJ series was developed specifically for surface-mount transient suppression in harsh environments-including automotive, industrial, and telecom-balancing high pulse power, tight VBR tolerance, and AEC-Q101 qualification.
FAQ
What is the clamping voltage of SMAJ51AHM3/I at its rated peak pulse current?
The SMAJ51AHM3/I has a maximum clamping voltage (VC) of 82.4 V at 4.9 A peak pulse current (10/1000 μs waveform). This value is measured under standardized surge conditions and defines the upper voltage limit imposed on protected circuitry during transient events. The clamping performance remains stable across its operating temperature range of -55 °C to +150 °C, making SMAJ51AHM3/I suitable for under-hood automotive applications.
Is SMAJ51AHM3/I certified for automotive use?
Yes, SMAJ51AHM3/I is AEC-Q101 qualified, confirming its suitability for automotive electronic systems. The HM3 suffix indicates it is halogen-free and RoHS-compliant, meeting stringent environmental and reliability requirements for engine control units, body controllers, and ADAS modules. Certification covers stress tests including temperature cycling, humidity bias, and accelerated life testing per AEC-Q101 standards.
What does the "HM3" suffix mean in SMAJ51AHM3/I?
The "HM3" suffix in SMAJ51AHM3/I denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. It distinguishes this variant from E3 (RoHS-compliant only) and HE3 (AEC-Q101 + RoHS, non-halogen-free) versions. The HM3 grade satisfies automotive OEM material declarations and supports sustainability goals without sacrificing electrical or thermal performance-identical VWM, VBR, and PPPM ratings apply.
Can SMAJ51AHM3/I be used in bidirectional protection circuits?
No, SMAJ51AHM3/I is a unidirectional TVS diode and must not be used for bidirectional protection. Its cathode band marking and asymmetric IV characteristics are designed for single-polarity clamping-typically placed between a positive rail and ground. For bidirectional applications (e.g., AC lines or differential buses), the SMAJ51CA family (e.g., SMAJ51CAHM3/I) is required, which exhibits symmetrical breakdown in both directions.
What is the thermal resistance of SMAJ51AHM3/I, and how does it affect PCB layout?
SMAJ51AHM3/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on minimum recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain safe operation at full 400 W pulse rating, designers must adhere to this pad layout and avoid excessive trace length or isolation. Exceeding TJ = +150 °C risks parametric shift or permanent degradation-thermal derating curves in the datasheet guide safe repetitive surge duty cycles.
SMAJ51AHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 4.9A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ51AHM3/I FAQ
1.How can I place an order for SMAJ51AHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51AHM3/I on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SMAJ51AHM3/I reliable?
The price and inventory of SMAJ51AHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51AHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ51AHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51AHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51AHM3/I?
SMAJ51AHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51AHM3/I order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SMAJ51AHM3/I?
For technical support, including SMAJ51AHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51AHM3/I requirements.
6.How does Aetrix verify that SMAJ51AHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ51AHM3/I products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMAJ51AHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ51AHM3/I?
All SMAJ51AHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51AHM3/I, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SMAJ51AHM3/I part is unused and in its original packaging.
Return procedure for SMAJ51AHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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